Discussion
In the present study we find LSG to have acceptable morbidity-rates and to be an effective procedure for weight loss and resolution of comorbidities. LSG had high resolution rates for T2DM, hypertension, hyperlipidemia, sleep apnea, musculoskeletal pain, snoring, urinary leakage and amenorrhea. The BMI and the prevalence of obesity-related diseases were stable between 12 and 24 months postoperatively. Between 85 and 90% of patients were taking some kind of vitamin and/or mineral supplement at follow-up.
In general, the reported complication rates for LSG are low despite high surgical risks in this patient group. Shi et. al. systematically reviewed major perioperative complications for LSG and found a mean ± SD of 1.17 ± 1.86% for leaks and 3.57 ± 5.15% for bleeding respectively. In order to reduce our leak-rate we have become particularly careful not to use heat-creating instruments close to the stomach wall at the cardia where both leaks occurred. In an attempt to reduce bleeding, we have changed our regime for prophylaxis against thrombosis in that the prophylaxis is started postoperatively and at reduced dosage. Other measures that could influence the rate of bleeding would be the use of different stapler cartridges and buttress material. There is currently no clear consensus on how the surgical technique is optimally performed, which makes it even more important to continuously evaluate the results at different centers.
We are only presenting resolution and not changes in the degree of severity of the obesity-related diseases or conditions, these results therefore represent an underreporting of the patients' improvement. Remission rates for T2DM, hypertension, hyperlipidemia and sleep apnea are higher among our patients than among sleeve- and gastric bypass operated patients in the study by Zhang et al., but our gastroesophageal reflux-rate is also higher. This could be due to differences in the surgical technique as we used a somewhat smaller boogie (32 versus 38/40 Fr), and we start the resection closer to the pylorus. For infertility, we observed a reduction in infertility rate of 55.0% at two years, but as pregnancy was strongly discouraged for the first 12 months after the operation, the study is dependent on 36 months data for completion of the infertility data according to the definition. The regain of a normal menstrual cycle in all amenorrheic premenopausal females is remarkable.
Association between LSG and GERD has been systematically reviewed, finding both a significant increase and a significant decrease in GERD after LSG. Our study shows a significant increase in GERD after the operation, even though five of our fifteen patients who were treated for GERD symptoms preoperatively had resolution of their GERD symptoms postoperatively. Our advice has been to have smaller meals at increased frequency and consume foods at slower rates with sufficient chewing, which might have some effect in reducing GERD-symptoms as Melissas et. al. have also experienced. In accordance to the experience of Nocca et. al. it is also our experience that the patients with GERD subjectively have a good effect of proton pump inhibitors. Howard et. al., who had a one year GERD rate of 21.0%, declare that all of their GERD patients were "extremely happy with their surgery" and "would choose the procedure again". Despite Howard et. al.'s findings, GERD is a potential drawback for the LSG and more work is being done in order to reduce the risk for GERD after LSG.
A high prevalence of micronutrient deficiencies among morbidly obese prior to bariatric surgery has been observed, a proposed consequence of malnutrition and/or altered bioavailability to micronutrients due to reduced dietary intake, reduced levels of hydrochloric acid and intrinsic factor. The number of patients with ferritin levels below reference range in our data increased significantly, similar to the findings of Himpens et. al.. Himpens et. al. also found cobalamin deficiency one and three years after LSG, which together with iron-related deficiencies are the most common deficiencies after bariatric surgery. The number of patients with cobalamin-deficiency was not altered in our study, but 27% and 29% of the patients were substituted with folic acid or cobalamin respectively already one year after surgery. Unfortunately, we do not know whether this substitution was based on low serum values for these vitamins or not. Our findings highlight a need for further exploring the necessity of folic acid, cobalamin, iron and possibly calcium-substitution in LSG patients before making any general recommendations.
Values for albumin and ALT showed significant improvement after the operation, and ALT levels remained significantly lowered at 24 months. Obesity is associated with non-alcoholic fatty liver disease (NAFLD), and resolution of NAFLD has been proven after bariatric surgery. Improvement of liver-associated biochemical variables due to resolution of NAFLD is therefore a probable explanation of our finding.
LSG has been found to be equally as safe and effective for weight loss and resolution of comorbidities as the Roux-en-Y gastric bypass (RYGBP) in the short term, and as the small bowel is not transected and no mesenteric defects are created, the risk for long term complications as jejunal ulcers and internal hernias are avoided. Also, further conversion to BPDDS or RYGBP if inadequate weight loss or weight regain should occur makes LSG a good option among the bariatric procedures. Long term effects of LSG are, however, still limited in terms of possible weight regain, side effects and persistence of comorbidity resolution.